1. Field of the Invention
The present invention relates to a weather strip for a motor vehicle having a molded joining portion, and a method for forming that weather strip by joining extruded weather strip portions with the molded joining portion.
2. Description of the Prior Art
In a motor vehicle, as shown in FIG. 10, a body flange is formed around a door opening 1 of the vehicle body, and a weather strip is attached to this body flange.
FIGS. 11 and 12 illustrate one example of a conventional weather strip for attachment to the body flange of a motor vehicle. Weather strip 2 is composed of extruded weather strip portions 2A, 2B and a joining portion 2C which joins the extruded weather strip portion 2A, 2B at the portion A of FIG. 10. This joining portion 2C is generally formed by molding (U.S. Pat. No. 4,884,370).
Each of the extruded weather strip portions 2A, 2B has a trim portion 3 having a U-shaped cross-section and a tubular sealing portion 4 which projects from one side surface of the trim portion 3. An insert 35 is embedded in the trim portion 3. Flange retaining lips 5 project obliquely inwardly from opposed inner surfaces of the trim portion 3 for retaining the body flange of the vehicle body.
FIG. 12 illustrates a bottom side of the molded joining portion 2C of the weather strip 2, and FIGS. 13 and 14 illustrate a cross-section of a mold for forming the joining portion 2C taken along the lines XIII--XIII and lines XIV--XIV, respectively of FIG. 12.
The trim portion of the molded joining portion 2C has no flange retaining lips. A slit 30 into which the body flange of the motor vehicle is to be inserted, opens from the bottom of the molded joining portion 2C.
The slit 30 is formed by a core plate 8 during molding. The core plate 8 has a flat board like flange portion 81 having a thickness corresponding to the body flange.
In order to join the weather strip portions 2A, 2B, ends of these weather strip portions 2A, 2B are spaced apart by a predetermined amount. Then, both ends of the flange portion 81 of the core plate 8 are respectively inserted into the trim portions 3 of the weather strip portions 2A, 2B. FIG. 14 illustrates the state where one end of the flange portion 81 of the core plate 8 is inserted into the trim portion 3 of the weather strip portions 2A.
Ends of the extruded weather strip portions 2A, 2B are mounted on the mold 6 with the core plate 8 positioned in a cavity 9 of the mold 6, as shown in FIG. 13. This cavity 9 is defined by mold members 6a, 6b, 6c of the mold 6. A rubber material is injected into the cavity 9 from a gate 7 provided between the mold members 6b, 6c. Thus, the joining portion 2C joining the weather strips 2A, 2B is molded.
In the conventional joining method, between the flange portion 81 of the core plate 8 and the facing inner surfaces of the trim portions 3 of the extruded weather strip portions 2A, 2B, openings 90 are formed on both sides of the flange retaining lips 5, as shown in FIG. 14. These openings 90 communicate with the cavity 9 of the mold 6 so that a portion of the rubber material injected into the cavity 9 flows out of the cavity 9 into openings 90.
The flow of the rubber material into these openings 90 causes a shortage of the rubber material within the cavity 9 so that the rubber material tends not to reach a narrow part 91 (FIG. 13) of the cavity 9, which is far from the gate 7. As a result in the resulting weather strip may be separated at the joints between the molded joining portion and the ends of the extruded weather strip portions.